: Approximately 150,000 to 500,000 infants greater than 34 weeks gestational age are admitted to NICUs annually who are at risk for systemic infection. These infants all receive systemic antibiotic therapy. However, the vast majority of these infants are not infected, but rather have symptoms that are secondary to other medical conditions. The current standard of care for evaluating neonatal sepsis is blood culturing, which lacks sensitivity and is not informative prior to at least 24 to 46 hours. As a result, there is prolonged use of antibiotic therapy in many newborns that could be shortened if a more rapid test to rule out sepsis was available. This application proposes to investigate two potential tests, a PCR-based amplification assay for detecting bacterial 16S ribosomal DNA and an ELISA-based assay for defensins, to determine their usefulness as early predictors of systemic neonatal infection.